Reed switch

ABSTRACT

A sealed switch having at least two reed-shaped magnetic poles of resilient metal, which respond to the surrounding magnetic field and cause contacts on their free ends to touch to each other, and also having an atmosphere confined to the area of and around said poles by a sealing means thereabout, which switch is characterized in that at least one of said reed-shaped poles is a partly flattened pipe of magnetic metal. The part of said metal pipe, which is bonded to a sealing means such as a glass envelope, may be utilized as a tube for exhausting air from and admitting the confined gas to the envelope.

O Unlted States Patent 1151 3,639,867

Tanimura et al. 1 5] Feb. 1, 1972 1 REED SW C 3,541,483 11/1970 11m ..335/154 [72] Inventors: Shigeru Tanimura, Kyoto; Norio Maejima, FOREIGN PATENTS OR ppuc o s Kameoka; Kilokazu Yoshimura, Osaka; Seisuke Himda Ikeda, n f Japan 1,509,639 12/1967 France ..335/l5l [73] Assignee: Omron Tateisi Electronics Co., Ukyo-ku, p i E i -B rnard A, Gilheany Kyoto, Japan Assistant Examiner-42. N. Envall, Jr. [22] Filed: Mar. 17 1970 At1arneyCra1g,Antonell1 & H1"

[211 App]. No.: 20,336 [57] ABSTRACT A sealed switch having at least two reed-shaped magnetic [30] Foreign Application Priority Dat poles of resilient metal, which respond to the surrounding magnetic field and cause contacts on their free ends to touch Mar. 17, 1969 Japan ..44/20l89 to each other and also having an atmosphere fi d to the area of and around said poles by a sealing means thereabout, U-S- witch is characterized in that at least one of aid reed. [51] Int. Cl. ..H0lh 51/28 ha d p les is a partly flattened pipe of magnetic metal. [58] Field of Search ..335ll5l-l54 The part of sald metal plpe, whlch 1s bonded to a sealmg [56] References Cited means such as a glass envelope, may be utilized as a tube for exhausting air from and admitting the confined gas to the en- UNITED STATES PATENTS p 3,439,302 4/ l 969 Perreault ..335/ 154 5 Claims, 6 Drawing Figures PATENTED FEB 11972 31639.86?

SHEET 1 OF 2 ATTORNEY REED swrrcrr REED SWITCH having two or more contacts, two or more magnetic pole means for responding to a magnetic field applied from outside to drive the contacts,,and also having a confined atmosphere confined to the area of and around said poles by a sealing means thereabout.

As is well known, a reed switch comprises at least one reed made with resilient magnetic metal sealed in an enclosure. The conventional reed switches comprise a pair of reeds of the same size and material. However, it is found that a reed switch having a pair of reeds which are of the same size and material is likely to have more chattering and less wiping actionof the contacts, in comparison with the one having a pairIof reeds which are of different size or material.

There has been a proposal for constituting a reed switch of a pair of magnetic poles, of which one is a conventional reed and the other is a rigid pipe of magnetic material. However, such proposed reed switch has a drawback in that its pickup and release ampere-turns of response to a surrounding magnetic field is too high, namely the sensitivity is too low, due to the fact that one of said pair of magnetic poles does not move.

The reed switch of the present invention comprises at least two reed-shaped magnetic poles of resilient metal which respond to the surrounding magnetic field to cause contacts on their free ends to touch each other, an atmosphere confined to the area of and around said poles bya sealing means thereabout, and characterized in that at least one of said reed shaped poles is a partly flattened part of a pipe of resilient magnetic metal. i

One object of the present invention is to provide a magneti cally responsive switch in which chattering of the contacts is considerably'reduced as compared to conventional switches ofasimilartype. r

Another object of the present invention is to provide a magnetically responsive switch in which more wiping action is obtainable in comparison with conventional switches of this type. 1

A further object of the present invention, is to provide a magnetically responsive switch in which a part of a reed is used as a tube for exhausting air from and admitting confined gas to the switch.

2 teem-which ismade by shaping into a reed part 23, a part of a solid rod 21 made of a resilient and magnetic metal, such as ferronickel alloy'consisting of, for instance, 48 percent ironand 52percent nickel.

The other reed l has a special construction that characterizes the present invention. Namely, the reed l is made by shaping into a reed part 13, a part of a pipe 11 of a resilient and magnetic material such asferronickel alloy. An illustrated method of flattening a, part of the pipe ll by pressing work to form a'reed part 13, can be employed in shaping the pipe II to I the reed part 13. An inside hole 14 is made at the innermost endof'the pipe 11 by, for instance, shearing a part proximatmixed gas such as nitr'ogengas containing 3 percent of These and other objects ofthisinvention will become apparent from the following detailed description of preferred switch embodiments with reference to the accompanying drawing, in which:

FIG. 1 is a sectional side view of a principal part ample embodying the present invention;

FIG. 2 is an enlarged perspective view of a reed used in the reed switch shown in FIG. 1;

FIG. 3 is a sectional side view of a principal part of a second example embodying the present invention;

FIG. 4 is an enlarged perspective view of a reed used in the reed switch shown in FIG. 3; r

FIG. 5 is a side view of another reed switch embodying the present invention, and

FIG. 6 is a plan view of an example of an input device employing the reed switch shown in FIG. 5.

Since the construction of the switches shown in FIGS. 1-2, 3-4 and 5-6 have common features, the following description of the elements making up the switch of the invention will be applicable to each of the figures, and corresponding reference numerals will be used in each of the figures for corresponding elements.

In the first example illustrated by FIGS. 1 and 2, a pair of reeds l and 2 are capsulated in a sealing means, namely glass tube or envelope 3. The reeds l and 2 constitute a pair of magnetic poles which respond to the surrounding magnetic field applied from outside. The reed 2 is a conventional type of hydrogen gas..lnthe enclosure, free end tipslS and '25 of the reed parts 13 and 23 are held in position with a specified gap between them in the absence of an applied magnetic field so as to for'riia pair of electric contacts. r

In the reed switch described above, the pipe 11 connected to a space'3l in the enclosure 3 through the hole 14 can be utilized'as a tube for exhausting air from and admitting the mixed gas into the space 31. In case of such utilization of the pipe 11, sealing-ofi of the tube after filling thegas can be done,-for instance, by pinching down'a part of the pipe 11 outside theenclosure 3, or welding or soldering the same so as to effect aseal. A coil 4 is provided for applying a'magnetic field to the magnetic poles. t r

In the reed switch of the foregoing example, when the rec part 13, is of the same, length, same width, same thickness and ing action between the contacts are observed. Accordingly,

the occurrence of rugged surfaces on the contacts is prominently minimized. Moreover, the reed switch has a satisfactorilylow pickup and release ampere-turnsmagnetic field value, because both the reeds have low compliances- In theriianufacture of the reed switch of the present invention, the space in the enclosure can be calmly sealed without any mechanical shock after thermal treatment for demagnetization and subsequent filling of the mixed gas at adesired pressure into the enclosure, thereby ensuring the effect of the demagnetizationtreatment, hence, satisfactory characteristics as designed. Thus, the constitution according to the present invention enables filling of the confined gas into the enclosure, at the most desired atmosphere, for instance, about 1.03 atm., which ishigher than, and hardly obtainable in, the conventional reed switch construction- In the second example illustrated by FIGS. 3 and 4, a small outsidehole 16 is opened on a part of the pipe 11 exposed outside the. enclosure 3, and the outer end of the pipe 11 is pinched down to form a sealed end 17. The other parts are constituted similarly to the foregoing first example. The reed switch of this example has the feature that sealing of the space 31 in the enclosure 3 can be made easily as well as calmly by closing the small outside hole 16 on the pipe 11 by, for instance, electric welding or soldering.

In the third example illustrated by FIGS. 5 and 6, the outer ends of'the reed parts 13 and 23 are shaped into flat terminal tips 18 and 28, respectively, in a fashion that the faces of the flat terminal tips 18 and 28 are positioned at a specified angle, for instance, from the faces of the reed parts 13 and 23. In

consequence of the above construction, this reed switch can be installed in a slit 53 on 'a printed circuit board 5, at an accurate specified angle between the faces of the reed parts [3, 23

and a face of the printed circuit board 5, by soldering the flat terminal tips 18 and 28 to printed conductors 52 and 52, respectively, on the board 5. A moving permanent magnet 6 is installed so as to be moved in a direction parallel with the axis of the reed switch by a driving rod 61, which can be connected to, for instance, a pushbutton of a keyboard (not shown). A reset spring 62 and a spring stopper 63 are provided to enable automatic resetting of the magnet 6.

In the device described above referring to FIG. 6, the distances of each of the reed parts 13 and 23 from the permanent magnet 6 when it comes immediately above reeds l3 and 23 are almost equal to each other, enabling accurate and reliable response of the reed switch to the position of the moving permanent magnet 6.

While we have shown and described only one embodiment in accordance with the present invention, it is understood that the same is not limited thereto but is susceptible of numerous changes and modifications as known to those skilled in the art, and we therefore do not wish to be limited to the details shown and described herein but intend to cover all such changes and modifications as are encompassed by the scope of the appended claims.

What is claimed is:

1. A reed switch comprising at least two reed-shaped magnetic poles of resilient metal responsive to a surrounding magnetic field for causing contacts provided on their free ends to touch each other, and an atmosphere confined to the area of and around said poles by a sealing means provided thereabout,

characterized in that at least one -of said reed-shaped magnetic poles is a partly flattened reed part of a pipe of resilient magnetic metal, wherein said one of said reed-shaped magnetic poles comprises a flattened reed part which extends to one end of said pipe and which is enclosed in said sealing means, a flat terminal tip made by flattening a part of said pipe extending to the other end of said pipe, and an unflattened part to which said sealing means is bonded and which lies in between said flattened reed part and said flat terminal tip part, and wherein a first hole is opened in the unflattened part of the pipe enclosed by said sealing means so as to' connect the enclosed space inside the sealing means to the hollow inside of the pipe and a second hole is provided in the unflattened part of the pipe outside said sealing means so as to connect the inside of the pipe to the outside.

2. A reed switch as defined in claim 1, wherein the faces of said flat terminal tips are positioned at a specified angle to the faces of said reed parts.

3. A reed switch as defined in claim 2, wherein said specified angle is approximately 4. A reed switch as defined in claim 1, wherein said first hole is opened at the innermost end of the remaining part of pipe that is near the fixed end of the reed part.

5. A reed switch as defined in claim 1, wherein each of said reed-shaped magnetic poles is so shaped that the longitudinal axisof the reed part does not run even with the longitudinal axis of the remaining part of the pipe. 

1. A reed switch comprising at least two reed-shaped magnetic poles of resilient metal responsive to a surrounding magnetic field for causing contacts provided on their free ends to touch each other, and an atmosphere confined to the area of and around said poles by a sealing means provided thereabout, characterized in that at least one of said reed-shaped magnetic poles is a partly flattened reed part of a pipe of resilient magnetic metal, wherein said one of said reed-shaped magnetic poles comprises a flattened reed part which extends to one end of said pipe and which is enclosed in said sealing means, a flat terminal tip made by flattening a part of said pipe extending to the other end of said pipe, and an unflattened part to which said sealing means is bonded and which lies in between said flattened reed part and said flat terminal tip part, and wherein a first hole is opened in the unflattened part of the pipe enclosed by said sealing means so as to connect the enclosed space inside the sealing means to the hollow inside of the pipe and a second hole is provided in the unflattened part of the pipe outside said sealing means so as to connect the inside of the pipe to the outside.
 2. A reed switch as defined in claim 1, wherein the faces of said flat terminal tips are positioned at a specified angle to the faces of said reed parts.
 3. A reed switch as defined in claim 2, wherein said specified angle is approximately 90*.
 4. A reed switch as defined in claim 1, wherein said first hole is opened at the innermost end of the remaining part of pipe that is near the fixed end of the reed part.
 5. A reed switch as defined in claim 1, wherein each of said reed-shaped magnetic poles is so shaped that the longitudinal axis of the reed part does not run even with the longitudinal axis of the remaining part of the pipe. 